At present the control of a display in telecommunication equipment, for example when playing different games, is generally based on using a mouse or different joysticks. When portable equipment such as handheld computers or phones are concerned, such solutions seem clumsy and impractical; a mouse may, for example, be of the same size as the entire apparatus. Likewise, if the motoric co-ordination or manual power of a terminal user have weakened due to injury or some other circumstance, such as age, the use of a mouse or joystick can be difficult. Therefore, a need is created to solve the display control of portable telecommunication equipment in particular in some other ways.
As component technology advances, new components have appeared on the market, such as acceleration sensors and proximity sensors. An acceleration sensor is generally an electromagnetic component generating to its output an electric signal corresponding to the acceleration. An acceleration sensor may presently be implemented in various ways, for example using a piezoelectric or piezoresistive crystal. The acceleration sensors may also be based on the motion of the mass. In such a case the motion of this mass is measured, for example capacitively, in order to determine the acceleration.
A change in the charge distribution of the piezoelectric crystal is comparable with the strength put upon the crystal. A piezoelectric crystal converts the mechanical labor into electricity and vice versa. In the piezoresistive crystal, in turn, the electric charge of the crystal is comparable with the power put upon the crystal.
The proximity sensors can be implemented using optical components. The optical proximity sensors are based on sending and receiving light of different wavelenghts. The focused light sent from a transmitter is reflected back from the target, the receiver receives the reflected signal and converts the signal to distance information, for example. The proximity sensors can also be implemented using other techniques, for example, pyro sensors sensitive for thermal radiation.